In flue gases discharged from boilers and incinerators which combust coal and heavy oil, components such as sulfur oxides (SOx), nitrogen oxides (NOx), carbon dioxide (CO2), carbon monoxide (CO), HCl, NH3, and other components are contained.
One example of gas analysis devices for analyzing the amounts of the components contained in a gas is as follows. The device includes a probe arranged so as to intersect a gas flow path in a pipe, and measurement light emitted from a light source to the gas is reflected by a reflector arranged at the tip of the probe, so that the concentration of a component of the sample gas is analyzed based on the information of the reflected measurement light (for example, refer to patent document 1).
The probe of the gas analysis device is in the form of a hollow pipe through which the measurement light passes. The probe is arranged so as to intersect with the gas flow path in the flue. An annular flange is fixed on the probe, and the flange is attached to a side wall of the pipe.
At the proximal end of the probe, a light emitting unit which emits measurement light into the probe, and a photodetector for receiving the reflected light are provided. At the tip of the probe, a reflector is provided for reflecting the measurement light from the light emitting unit to the photo detector side.
In the above gas analyzing device, gas in flue is introduced into the probe by diffusion, and the measurement light emitted from the light emitting unit and reflected by the reflector is received by the photo detector, so that the components in the gas can be analyzed based on the characteristics of this measurement light.